HistoricalInteresting ChemistryEnergyHigh Chemical ShiftsNew HampshireChemical Sciences

Fine-tuning a (hydrogen) bond into symmetry.

https://doi.org/10.59350/ng5sb-f8g15
Published in Henry Rzepa's Blog

Sometimes you come across a bond in chemistry that just shouts at you. This happened to me in 1989[cite]10.1039/C39890001722[/cite] with the molecule shown below. Here is its story and, 26 years later, how I responded. To start at the beginning, there was a problem with the measured 1 H NMR spectrum; specifically (Y=H, Z=O) there are supposedly 16 protons, but only 15 could be located. What had happened to the 16th?

References

InChI=1S/C13H15N3O3.Na/c1-7(2)13(3)12(19)15-10(16-13)9-8(11(17)18)5-4-6-14-9;/h4-7H,1-3H3,(H2,15,16,19);/q;+1/p-1/t13-;/m1./s1GMAPXYNSJJBAAO-BTQNPOSSSA-O

C 13 H 14 N 3 Na 1 O 3

https://doi.org/10.14469/ch/189477
Published
Authors Henry S Rzepa, Imperial College London, Imperial College London, Henry S Rzepa

# nmr=giao scrf=(cpcm,solvent=chloroform) geom=connectivity opt freq e